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Selenium Benefits: Everything You Need to Know

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Selenium Benefits: Everything You Need to Know

Selenium is one of the lesser-known essential trace minerals and there’s no shortage of reasons to make sure our intake of selenium is optimized. As an essential micronutrient, selenium cannot be produced by the body and, as a result, it needs to be obtained through selenium-rich foods or supplementation. (21) From supporting our immune systems to protecting our bodies from degenerative disease, there are so many reasons to make room on our plates for foods high in selenium. (5)

What is selenium and how much do you need?

As an essential micromineral, selenium is needed by the body in small amounts. According to established Recommended Daily Allowances (RDAs), children need 20 mcg to 40 mcg of selenium per day and adults require 55 mcg per day to maintain optimal health. While recommendations don’t vary based on sex, nutrient needs increase to 60 mcg to 70 mcg per day for women who are pregnant or breast feeding. (9)

Person holding a handful of nuts

Known as one of the richest sources of selenium, just a handful of brazil nuts a day can go a long way in boosting selenium levels naturally. (24)

Top 5 selenium benefits

Interested in learning more about this underrated mineral? Read on to discover five important reasons to incorporate selenium-rich foods into your diet.

Provides antioxidant effects

In order to understand the role selenium plays as an antioxidant, we have to understand the role of free radicals. Free radicals are byproducts of normal cell metabolism and can also come from environmental stressors such as smoking, medications, and pollution. While free radicals are a very normal part of our biology, an abundance of free radical activity can contribute to oxidative stress, which is linked to many of the chronic, degenerative diseases, such as cancer, cardiovascular disease and autoimmune disorders. (1)(7) In order to counteract these free radicals, our body must make antioxidants or acquire them from the foods we eat in order to neutralize free radicals and prevent oxidative stress. This is where selenium comes in. Considered an antioxidant, optimal selenium intake can help reduce and protect against oxidative stress. (3)(21)

Strengthens the immune system

Selenium has been shown to be beneficial in enhancing the immune response and reducing inflammation, protecting the body against specific pathogens, such as viruses. Low serum levels of selenium have been shown to slow the response of immune cells. (6) Furthermore, dietary supplementation has been shown to be beneficial in the prevention and recovery of infections due to the influenza A virus. (25) Not only can this essential mineral protect against specific viruses, it has also been shown to slow disease progression in immune-compromised individuals with human immunodeficiency virus (HIV). Interestingly, low selenium serum levels have also been reported in patients who are HIV positive. (26)

Supports thyroid function

Did you know that the thyroid gland contains the highest amount of the selenium compared to any other organ in the body? Selenium is essential to thyroid function, as it is needed for the metabolism of thyroid hormones. Therefore, it comes as no surprise that selenium supplementation has been shown to be beneficial for individuals with thyroid disease. (28) For example, in patients with Hashimoto’s thyroiditis, supplementation of selenium has been shown to boost mood and overall quality of life. (27) It has also been demonstrated that low selenium serum levels can result in an increased risk for the development of thyroid disease. (29)

Woman getting her neck area inspected

Selenium is an essential micronutrient needed for optimal thyroid function (28).

Supports cancer prevention and therapy

Studies have shown that selenium’s antioxidant and anti-inflammatory effects may reduce the risk of developing certain types of cancers, such as breast, lung, prostate, and skin cancer. (4) Several studies have suggested that selenium supplementation can increase quality of life and decrease side effects in cancer patients undergoing radiotherapy treatment. (20) Another study specifically looked at selenium’s impact on patients undergoing gynecological radiation therapy, highlighting the mineral’s ability to reduce side effects like radiation-induced diarrhea. (8)

Reduces cognitive decline

The number of people who suffer from Alzheimer’s disease is staggering – five million Americans are living with the degenerative disease, and sadly, the numbers are steadily increasing. (2) Selenium, in combination with other lifestyle factors, may play a role in reducing oxidative stress that is believed to play an important role in the progression of Alzheimer’s disease. (23) Furthermore, brazil nuts, which contain one of the highest dietary sources of selenium, have been studied for their positive effects on cognitive performance. In adults with pre-existing cognitive impairment, brazil nuts have been shown to increase antioxidant activity, therefore reducing oxidative stress linked to cognitive decline. (22)

A diverse whole food spread

A diverse whole food diet composed of high-quality meats, eggs, and whole grains is the best way to ensure adequate selenium intake.

Foods high in selenium

Brazil nuts are one of the highest and most well-known dietary sources of selenium. (24) Along with Brazil nuts, some of the best sources of selenium are outlined below.

Sardines, sunflower seeds, and oat bran are among the top dietary sources of selenium. (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)

Should you supplement with selenium?

If you’re having a hard time obtaining selenium from dietary sources alone or you require it in greater amounts, consult with your integrative health care practitioner about adding a selenium supplement to your protocol in order to reach your RDA.

The bottom line

There are many reasons to ensure optimal selenium intake, from reducing oxidative stress and supporting immune and thyroid function to preventing cognitive decline and cancer Luckily, there is an abundance of selenium-rich whole foods from which to choose from in order to meet recommended amounts. In unique cases when supplementation is needed, it’s best to consult with your integrative healthcare practitioner to see if selenium supplementation is right for you.

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  1. Ai Pham-Huy, L., He, H., & Pham-Huy, C. (2008). Free Radicals, Antioxidants in Disease and Health. Free Radicals, Antioxidants in Disease and Health, 1.
  2. Alzheimer Statistics. (2020, October 12). Alzheimers.Net.
  3. Brenneisen, P., Steinbrenner, H., & Sies, H. (2005). Selenium, oxidative stress, and health aspects. Molecular Aspects of Medicine, 26(4–5), 256–267.
  4. Cai, X., Wang, C., Yu, W., Fan, W., Wang, S., Shen, N., Wu, P., Li, X., & Wang, F. (2016). Selenium Exposure and Cancer Risk: an Updated Meta-analysis and Meta-regression. Scientific Reports, 6(1), 1.
  5. Hoffmann, P. R., & Berry, M. J. (2008a). The influence of selenium on immune responses. Molecular Nutrition & Food Research, 52(11), 1273–1280.
  6. Hoffmann, P. R., & Berry, M. J. (2008b). The influence of selenium on immune responses. Molecular Nutrition & Food Research, 52(11), 1273–1280.
  7. Ju, W., Li, X., Li, Z., Wu, G. R., Fu, X. F., Yang, X. M., Zhang, X. Q., & Gao, X. B. (2017). The effect of selenium supplementation on coronary heart disease: A systematic review and meta-analysis of randomized controlled trials. Journal of Trace Elements in Medicine and Biology, 44, 8–16.
  8. Muecke, R., Schomburg, L., Glatzel, M., Berndt-Skorka, R., Baaske, D., Reichl, B., Buentzel, J., Kundt, G., Prott, F. J., deVries, A., Stoll, G., Kisters, K., Bruns, F., Schaefer, U., Willich, N., & Micke, O. (2010). Multicenter, Phase 3 Trial Comparing Selenium Supplementation With Observation in Gynecologic Radiation Oncology. International Journal of Radiation Oncology*Biology*Physics, 78(3), 828–835.
  9. National Institutes of Health. (2020, March 11). Selenium.
  10. Nutrition Value. (2020a). Beef, raw, ground, grass-fed.
  11. Nutrition Value. (2020b). Beef, raw, liver, variety meats and by-products.
  12. Nutrition Value. (2020c). Chicken, raw, ground.
  13. Nutrition Value. (2020d). Egg, fresh, raw, whole.
  14. Nutrition Value. (2020e). Fish, drained solids with bone, canned in oil, Atlantic, sardine.
  15. Nutrition Value. (2020f). Fish, raw, skipjack, fresh, tuna.
  16. Nutrition Value. (2020g). Nuts, unblanched, dried, brazil nuts.
  17. Nutrition Value. (2020h). Oat bran, raw.
  18. Nutrition Value. (2020i). Rice, raw, long-grain, brown.
  19. Nutrition Value. (2020j). Seeds, dried, sunflower seed kernels.
  20. Puspitasari, I. M., Abdulah, R., Yamazaki, C., Kameo, S., Nakano, T., & Koyama, H. (2014). Updates on clinical studies of selenium supplementation in radiotherapy. Radiation Oncology, 9(1), 125.
  21. Rayman, M. P. (2000a). The importance of selenium to human health. The Lancet, 356(9225), 233–241.
  22. Rita Cardoso, B., Apolinário, D., da Silva Bandeira, V., Busse, A. L., Magaldi, R. M., Jacob-Filho, W., & Cozzolino, S. M. F. (2015). Effects of Brazil nut consumption on selenium status and cognitive performance in older adults with mild cognitive impairment: a randomized controlled pilot trial. European Journal of Nutrition, 55(1), 107–116.
  23. Santos, J. R., Gois, A. M., Mendonça, D. M. F., & Freire, M. A. M. (2014). Nutritional status, oxidative stress and dementia: the role of selenium in Alzheimer’s disease. Frontiers in Aging Neuroscience, 6, 1.
  24. Silva Junior, E. C., Wadt, L. H. O., Silva, K. E., Lima, R. M. B., Batista, K. D., Guedes, M. C., Carvalho, G. S., Carvalho, T. S., Reis, A. R., Lopes, G., & Guilherme, L. R. G. (2017a). Natural variation of selenium in Brazil nuts and soils from the Amazon region. Chemosphere, 188, 650–658.
  25. Steinbrenner, H., Al-Quraishy, S., Dkhil, M. A., Wunderlich, F., & Sies, H. (2015). Dietary Selenium in Adjuvant Therapy of Viral and Bacterial Infections. Advances in Nutrition, 6(1), 73–82.
  26. Stone, C. A., Kawai, K., Kupka, R., & Fawzi, W. W. (2010). Role of selenium in HIV infection. Nutrition Reviews, 68(11), 671–681.
  27. Toulis, K. A., Anastasilakis, A. D., Tzellos, T. G., Goulis, D. G., & Kouvelas, D. (2010). Selenium Supplementation in the Treatment of Hashimoto’s Thyroiditis: A Systematic Review and a Meta-analysis. Thyroid, 20(10), 1163–1173.
  28. Ventura, M., Melo, M., & Carrilho, F. (2017a). Selenium and Thyroid Disease: From Pathophysiology to Treatment. International Journal of Endocrinology, 2017, 1–9.
  29. Wu, Q., Rayman, M. P., Lv, H., Schomburg, L., Cui, B., Gao, C., Chen, P., Zhuang, G., Zhang, Z., Peng, X., Li, H., Zhao, Y., He, X., Zeng, G., Qin, F., Hou, P., & Shi, B. (2015). Low Population Selenium Status Is Associated With Increased Prevalence of Thyroid Disease. The Journal of Clinical Endocrinology & Metabolism, 100(11), 4037–4047.


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